Various types of agricultural feed mixers are known. One type of mixer, known as a vertical axis mixer, utilizes a mixing tub having an open upper end and including at least one rotatable auger mounted about a vertical axis within the tub. The rotation of the auger causes feed within the tub to be agitated, chopped, and mixed.
Many of these mixers are mounted upon trailers that can be drawn behind a conventional agricultural tractor. They include drive systems that can be powered by the power take off of the tractor. Other types of mixers are mounted directly on a self-propelled vehicle and are driven by the internal combustion engine that also propels the vehicle. Alternatively, such mixers may be mounted in a stationary position and be provided with their own power source, or include a connection for a power take off.
One of the issues faced by such mixers is providing appropriate rotational force to the auger or augers. The amount of force required to rotate the augers can vary depending upon a number of factors, including the amount of feed in the tub, the stage of the mixing process, whether the augers are already rotating, and the type and condition of the feed. The difficulties in maintaining an appropriate input force to the augers can be exacerbated by variations in the amount of available power provided by the power take off from an agricultural vehicle, and by changing conditions within the material being mixed.
It is typically desirable to maintain a generally constant rate at which feed is discharged from the tub wherein the mixer is discharging the feed. This can be difficult to maintain as the amount of resistance provided by the feed against the augers decreases as the amount of feed in the tub decreases.
Another difficulty associated with this type of agricultural feed mixer is that it can be difficult to completely discharge and clean out all of the feed from the tub as some of the feed may tend to cling to the augers and remain within the tub.
Yet another difficulty faced in operating these vertical auger mixers is that one or more of the augers can stall or jam due to feed wedging between the walls on especially the floor of the tub and the augers. Furthermore, the augers can become stalled due to the feed being packed tightly around the augers during transportation.